Constitutive Modeling of Magneto-Mechanical Coupling Response of Magnetic Field-Induced Phase Transformations in NiMnCoIn Magnetic Shape Memory Alloys

The unique characteristic of magnetic field induced phase transformation of NiMnCoIn magnetic shape memory alloys (MSMAs) lies in the generation of large transformation strains under high constant stress levels. Motivated by experiments, a constitutive model is proposed to take into account magnetic field induced phase transformation from austenitic to martensitic phase. The working principle of such materials is described by the deformation of continua due to mechanical and magnetic forces. The cross coupling of mechanical and magnetic variables is captured by introducing nonlinear kinematics. In the present work, microstructure dependence of martensitic phase transformation is taken into account by introducing internal variables into the model. The constitutive response is derived in a consistent thermodynamic way.